Refrigerating apparatus



Feb 7, 17

Filed Jan. 10, 1966 M. N. SCHERZINGEW REFRIGERATING APPARATUS B EWEAEQ 2 Sheets-5heet l INVENTOR. MARK iv. SCHEIE'ZINGER A T TO/FA/EV 1967 M. N. SCHERZINGER 3,302,424

REFRIGERAT ING APPARATUS Filed Jan. 10, 1966 2 Sheets-Sheet 2 INVENTOR. MAR/1 Al. SCHIEfFZ/NGE/F BY {Wm A TTOR/VE V United States Patent "ice 3,302,424 REFRIGERATING APPARATUS Mark N. Scherzinger, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Jan. 10, 1966, Ser. No. 519,684 6 Claims. (Cl. 62--296) This invention is directed to refrigerating apparatus and more particularly to an improved mufi ling arrangement in a hermetically sealed motor-compressor unit having a direct external connection between the outlet of the compressor and the exterior of an enclosing shell of the unit.

In many refrigerant systems, especially those suited for association with domestic refrigerators, it is desirable to reduce the noise level during the operation of the refrigerant system as low as is practical andeconomical. One particular noise problem exhibited in such operative systems is that produced by virtue of the inherent fact that both rotary and reciprocal forms of refrigerant compressing devices are characterized by a pulsing gas flow on the discharge side of such devices. In order to eliminate or substantially'reduce the inherent noise characteristics of such pulsing gas flow, a wide variety of various mufiling apparatus have been incorporated in compressors to eliminate pulsations in the discharge side of the compressor. In the case of hermetically sealed motor-compressor units of the type including a direct external connection from the outlet of the compressor through the exterior shell thereof into a superheat coil for removing heat from the discharged refrigerant flow, such muflling has required the inclusion of an additional component in the relatively limited space confines of the interior of the hermetic shell unit. Such muffiing apparatus is not always readily placed within the space limitations present within a given compressor assembly and/ or add additional cost to the unit both from the standpoint of the material required to fabricate the mufiling apparatus and the cost of assembling the apparatus within the compressor.

Accordingly, an object ofthe present invention is to improve hermetically sealed motor-compressor units of the type including a direct exterior connection from the discharge of the compressor to an exteriorly located superheat coil and wherein the cooled refrigerant from the superheat coil is recirculated through the hermetically sealed space of the unit to both separate lubricant from the circulating refrigerant as well as to cool the operative components of the unit by the provision therein of improving low-cost muflling means located exteriorly of the compressor and separate therefrom and within the hermetically sealed space around the compressor without requiring any modification to either the compressor or the enclosing shell of the hermetically sealed motor compressor unit.

A further object of the present invention is to improve refrigerant apparatus of the type set forth in the preceding object wherein the low-cost mufiiing means utilizes a modified tubular fluid connection located within the hermetically sealed space within the unit for communicating the compressor discharge with the superheat coil.

Still another object of the present invention is to improve refrigerating apparatus of the type mentioned in the preceding object wherein the modified tubular fluid connection includes means therein for communicating the outlet of the compressor directly to the hermetically sealed space therearound so that a predetermined portion of the discharged refrigerant flow will pass into the hermetically sealed space and by-pass the superheat coil to muffle gas pulsations in the discharge conduit to the superheat coil.

3,3flZAZ4 Patented Feb. 7, 1967 Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is a View in vertical section of a hermetically sealed motor compressor unit including the present invention and shown in association with the schematically illustrated refrigerant system;

FIGURE 2 is a view in horizontal section taken along the line 2-2 of FIGURE 1;

FIGURE 3 is a view in vertical section taken along the line 3-3 of FIGURE 2; and

FIGURE 4 is an enlarged view in horizontal section taken along the line 44 of FIGURE 3.

Referring now to FIGURE 1, a refrigeration system 10 is illustrated including a hermetically sealed motor compressor unit 12 having an open-ended outer shell 14 of sheet metal material with a bottom end closure plate 16 secured thereto to form a hermetically sealed space 18 of a predetermined configuration determined by the dimensional configuration of a compressor unit 20 and a compressor drive assembly 22. Inmany refrigerating systems as, for example, those used in association with domestic refrigerators, it is desirable to minimize the outer configuration of the shell 1-4. Thus, the hermetically sealed space 18 about the compressor and compressor drive assembly 22 desirably is maintained at a minimum.

The refrigeration system 10 includes a conduit 24 for directing fluid from the hermetically'sealed space 18 to a condenser 26 from whence refrigerant passes through a suitable expansion device 28 representatively shown as an expansion valve. From the expansion device 28 the refrigerant passes through an evaporator coil 30 and thence through a fluid conduit 32 interiorly of the hermetically sealed space 18. The conduit 32 connects to an inlet conduit 34 which passes into an inlet opening 36 in the compressor 20.

The compressor 20 is shown representatively as being a rotary compressor of the form more specifically set forth in United States Patent No. 3,016,183 issued January 9, 1962, to Murphy et al. and as more specifically set forth in the Murphy patent, the compressor 20 includes a rotary gas pumping piston that draws fluid from the inlet opening 36 and discharges refrigerant under compression through an outlet opening 38 into a discharge conduit 40 which is connected to a fluid conduit 42 exteriorly of the shell 14 which, in turn, is connected fluidly to a superheat coil 44 that serves to remove heat from the compressed refrigerant gas. The cooled compressed refrigerant gas thence is passed through a con duit 46 and returned into the hermetically sealed space 18.

In the illustrated arrangement the compressor 20 includes an end plate 48 that is supported resiliently by springs 50 on a bracket 52 within the compressor. The end plate 48 also supportingly receives a stator block 54 of the drive assembly 22 which has an electrically energized coil 56 supported thereon connected to a terminal assembly 58 supported by the shell 14 in an opening therethrough. The drive assembly 22 also includes a rotor 60 that is secured to one end of a vertically disposed drive shaft 62 and responsive to energization of the coil 56 to rotate the shaft 62 so as to operate the pump piston secured to the opposite end thereof, as more specifically set forth in the Murphy patent.

In such arrangements, there is a substantial heat buildup in the drive assembly 22 as well as in the compressor 20 and the cooled compressed refrigerant directed into the hermetically sealed space 18 is passed over the drive motor assembly 22 and compressor 20 to cool them and thereby prevent an undesirable temperature increase within the shell 14.

Additionally, the passage of the discharge refrigerant back into the hermetically sealed space 18 and direction thereof through the space 18 allows any entrained lubricant in the refrigerant to be separated by gravity into an oil sump 64 formed in the bottom of the space 18.

One characteristic of the above-described refrigerant system is that there is a direct exterior connection from the discharge side of the compressor 20 to the superheat coil 44. In the past, in order to muflie the noise of a pulsing gas stream on the discharge side of the compressor 20, it has been necessary to provide a separate muflier exteriorly of the compressor shell 14 which necessitated additional fluid connections in the refrigerant system thereby requiring additional inspection and safeguards to assure that the system was gas tight. The presence of such additional connections in the system, of course, reduced the operational reliability of the system. Another solution to the problem of noise created by gas pulsations on the discharge side between the compressor and superheat coil in such systems has been to modify relatively simple compressors 21) to include builtin mufflers, thus increasing the cost of the unit both from the standpoint of additional components in the unit and that of fabricating and assembling the unit. Still another proposed solution has been to incorporate a separate muffler exteriorly of the compressor and within the space 13. This arrangement, however, requires a modification of dimensional configurations of the space 18 to make room for such an additional component in the system.

In accordance with certain principles of the present invention, the pulsing gas noises on the discharge side of the compressor have been reduced materially without utilizing any of the approaches set forth above. More particularly, and as best seen in FIGURES 2 through 4, the discharge conduit includes a vertically disposed loop portion 66 thereon which is located in spaced relationship to both the comperssor 20 and the inside surface of the shell 14. The loop includes a plurality of small diameter openings 68 representatively shown as being located at equally spaced points through the wall of the conduit loop portion 66. The opening 68 direct a predetermined portion of the gas discharged from the compressor 20 directly into the hermetically sealed space 18 whereby gas pulsations are muflled effectively directly within the space 18 prior to the flow of refrigerant exteriorly of the hermetically sealed motor compressor unit 12. This produces a subtsantially reduced noise level of operation in the unit. The amount of fluid passed directly into the chamber 18 effectively produces a simple resonator type of muffling effect in the system without requiring the addition of any separate mufller in the assembly and it has been found that the direct flow of discharged fluid into the hermetically sealed space 18 prior to passage of discharged fluid into the superheat coil 44 can be proportioned to obtain desired cooling of the operative components of the unit 12 without requiring the addition of cooling fans or the like in the system.

While the embodiment of the present invention as herein disclosed constitutes as preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a refrigerant system, a compressor including an inlet and an outlet and means for pumping fluid from said inlet through said outlet, means for driving said compressor, a shell enclosing said compressor and said drive means and forming a hermetically sealed space around said compressor and drive means, a first fluid conduit directed through said shell and fluidly connected to said compressor inlet, a second fluid conduit directed through said shell and connected to said compressor outlet, a superheat coil located exteriorly of said shell, means for fluidly connecting one end of said coil to said discharge fluid conduit, means for directing the opposite end of said coil interiorly of said shell, and means including a plurality of openings in said discharge fluid conduit for bleeding a predetermined portion of the refrigerant discharged from said compressor into said hermetically sealed space for muffling pulsating gas flow from said compressor into said superheat coil.

2. In the combination of claim 1 said openings including a pair of cross holes formed in said tube for directing pulsing gas flow through said tube in a plurality of directions from said tube interiorly of said hermetically sealed space.

3. In the combination of claim 1, an outlet fitting on said .shell for directing refrigerant returned from said superheat coil exteriorly of said shell, said outlet fitting being located on an opposite side of said shell from the point at which refrigerant is returned from said superheat coil into said shell whereby lubricant in the compressed refrigerant is separated from the compressed refrigerant therein prior to the passage of such refrigerant through said outlet fitting.

4. In the combination of claim 1, said compressor including a rotatable piston for pumping fluid, said drive means including a vertically disposed shaft connected to said rotatable piston and means including electrically energizable rotor means for rotating said vertically disposed shaft to drive said piston, said means in said discharge conduit including a generally vertically directed loop located in spaced relationship to the inner surface of said shell.

5. In the combination of claim 3, said means in said discharge fluid conduit for muffling gas pulsations from said compressor including a loop segment disposed within said hermetically sealed space in spaced relationship to said compressor and said shell, said looped conduit portion including openings .therein for directing a predetermined portion of the discharged fluid from the compressor into the hermetically sealed space while directing a substantially greater portion of the discharged refrigerant through the superheat coil for cooling the discharged refrigerant whereby the discharged refrigerant returned to said hermetically sealed space serves to remove heat buildup in said drive means.

6. In the combination of claim 5, said openings including a pair of cross holes formed in said tube for directing pulsing gas flow through said tube in a plurality of directions from said tube interiorly of said hermetically sealed space.

References Cited by the Examiner UNITED STATES PATENTS 2,198,258 4/1940 Money 62296 3,066,857 12/1962 McCloy 230232 3,155,312 11/1964 Douglas 230-232 3,187,991 6/1965 Roelsgaard 62296 WILLIAM J. WYE, Primary Examiner. 

1. IN A REFRIGERANT SYSTEM, A COMPRESSOR INCLUDING AN INLET AND AN OUTLET AND MEANS FOR PUMPING FLUID FROM SAID INLET THROUGH SAID OUTLET, MEANS FOR DRIVING SAID COMPRESSOR, A SHELL ENCLOSING SAID COMPRESSOR AND SAID DRIVE MEANS AND FORMING A HERMETICALLY SEALED SPACE AROUND SAID COMPRESSOR AND DRIVE MEANS, A FIRST FLUID CONDUIT DIRECTED THROUGH SAID SHELL AND FLUIDLY CONNECTED TO SAID COMPRESSOR INLET, A SECOND FLUID CONDUIT DIRECTED THROUGH SAID SHELL AND CONNECTED TO SAID COMPRESSOR OUTLET, A SUPERHEAT COIL LOCATED EXTERIORLY OF SAID SHELL, MEANS FOR FLUIDLY CONNECTING ONE END OF SAID COIL TO SAID DISCHARGE FLUID CONDUIT, MEANS FOR DIRECTING THE OPPOSITE END OF SAID COIL INTERIORLY OF SAID SHELL, AND MEANS INCLUDING A PLURALITY OF OPENINGS IN SAID DISCHARGE FLUID CONDUIT FOR BLEEDING A PREDETERMINED PORTION OF THE REFRIGERANT DISCHARGED FROM SAID COMPRESSOR INTO SAID HERMETICALLY SEALED SPACE FOR MUFFLING PULSATING GAS FLOW FROM SAID COMPRESSOR INTO SAID SUPERHEAT COIL. 